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DIY Planar magnetic heapdhones in details

post #1 of 44
Thread Starter 

Hi! It's my first post on this forum and I would like to start a thread where I'll tell you my story of building full size planar magnetic headphones.

Fankly speaking, I'm rather new in Head-Fi (but not new in Hi-Fi ;) ) and I hope to hear your opinion (and maybe some tips!) about my work. I've started building headphones exactly 1 year ago and now I think I have something interesting to tell to the world.

 

 

 

What are my goals?

 

1. To build a full size open planar magnetic headphones

2. Achieve a sound of a really high level ( my landmarks are Audeze LCD-3 and Hifiman He-1000)

3. Headphones should be ready at least for a small series

4. Net cost 100-150$

 

So the story begins...

 

My first step was to make a simple planar magnetic transducer. From my point of view starting from the beginning with building a headphone is a really bad idea. I'm not novice in making non-dynamic transducer: i've already built electrostatic and plasma speakers, so making an isodynamic speaker wasn't a difficult task for me. I went to market, bought same magnets, opened Corel Draw, made simple drawings and cut with laser a few plastic and metal parts.

Next day I received such result :

 

 

And same speaker with one sided magnet system:

 

 

If Admin will consider my post worthy I ask to move this thread to DIY forum. As a novice I can only start a new thread in "Introductions, Help and Recommendations"

post #2 of 44

Hoo, that's really cool. I'm currently in the process of working on my own planar headphones and have a thread up for them. Progress isn't nearly as fast as yours though. Hope something interesting comes outta yours. Will be watching.

post #3 of 44
Thread Starter 

Wafflelron, hi! I read your thread and you made a mistake in tracing diaphragm

So let me explain how I did those mini speakers and I'm sure you understand about what I'm talking about

 

Step 1:

 

Tracing diaphragm

 

Please look, current in all 4 groups of traces flow in the same direction.

 

Step 2 - placing magnets between group of traces. How I made it I've shown on picture.

 

Step 3 - making a housing. That's the most simple. Just draw anything you want in any vector editor and cut it with laser.

 

Gray details are from steel, purple are from plastic.

If somebody is interested I'll explain how to make a membrane with conductor lines, what material should be used and how to assemble this.

post #4 of 44
Quote:
Originally Posted by Garuspik View Post
 

Wafflelron, hi! I read your thread and you made a mistake in tracing diaphragm

So let me explain how I did those mini speakers and I'm sure you understand about what I'm talking about

 

Step 1:

 

Tracing diaphragm

 

Please look, current in all 4 groups of traces flow in the same direction.

 

Step 2 - placing magnets between group of traces. How I made it I've shown on picture.

 

Step 3 - making a housing. That's the most simple. Just draw anything you want in any vector editor and cut it with laser.

 

Gray details are from steel, purple are from plastic.

If somebody is interested I'll explain how to make a membrane with conductor lines, what material should be used and how to assemble this.

Yeah I had realised that shortly after posting. Never got around to fixing/updating the thread. I've made an updated trace already. I don't have a a laser cutter, but I have access to a 3D printer at one of the courses I'm taking. I've just been real busy so making the housing hasn't been on my priority list. My real problem at this point is making the headband, but even that is a solved issue at this point, as I have an old Beyerdynamic style headband I can sacrifice. 

 

Thanks for the advice though. I'd surely be interested in what materials you've used though. I'm using Kapton film for mine, which I've never seen used before. I was advised to use Kapton over Mylar, but I may do a version of both.

post #5 of 44
Thread Starter 

For membrane I use Dupont Pyralux. It's some sort of kapton + copper. I've achieved 0.15 width of trace.

Here photos of my first headphone prototype.

 

 

 

 

post #6 of 44
Thread Starter 

Made some measurements of this prototype:

 

For a made-in-evening prototype with magnets bought in nearby store and one sided magnet system it sounds really well and I decided to order custom magnets and build a serious headphone transducer. If someone is interested I'll tell what I achieved and explain how it was made.

post #7 of 44

Awesome work.

Please explain the whole process once you receive the new magnets. How you etched the thin kapton film and so on...

post #8 of 44
Thread Starter 

I've already received custom magnets. Frankly speaking, this project started rather long ago but it's not interesting to post everything in one day ;)

 

So, before I've ordered custom magnets I've visited my local hi-end headphones store. I took with me my favourite music, screwdriver :biggrin: and whiskey (to an owner as a 'thank you' for possibility to open hi-end planar headphones and look what's inside.

 

I've listened and opened to look inside Audeze LCD 4, Hifiman He-1000, Hifiman He-560, and some less pricy Fostex. I noticed that all mentioned headphones has relatively small membrane compared to the size of the cup. I consider this to be a huge mistake in their construction. Let's change this! I've tried to maximize moving area of membrane and draw such thing:

Outer diameter of cup is 110 mm. Diameter of the moving part of diaphragm is 82 mm. That's about twice as big in comparison with He-1000 (which sound I really like).

To make such transducer I've ordered 50 pcs of 85*3*3  N50 neodymium magnets.

 

How I assembled that and what was the result I'll tell later.

post #9 of 44

Just out of interest, what adhesive did you use to attach the membrane to the acrylic? 

post #10 of 44
Thread Starter 
Quote:
Originally Posted by WaffleIron View Post
 

Just out of interest, what adhesive did you use to attach the membrane to the acrylic? 

Very good question! I've tried 5-6 glues before I've found perfect variant:

post #11 of 44

Very interesting project.  :beerchug:

post #12 of 44

Subscribed, very interested in how this comes together for you, very cool.

post #13 of 44
Quote:
Originally Posted by WaffleIron View Post
 

Yeah I had realised that shortly after posting. Never got around to fixing/updating the thread. I've made an updated trace already. I don't have a a laser cutter, but I have access to a 3D printer at one of the courses I'm taking. I've just been real busy so making the housing hasn't been on my priority list. My real problem at this point is making the headband, but even that is a solved issue at this point, as I have an old Beyerdynamic style headband I can sacrifice. 

 

Thanks for the advice though. I'd surely be interested in what materials you've used though. I'm using Kapton film for mine, which I've never seen used before. I was advised to use Kapton over Mylar, but I may do a version of both.

 

 

I believe we've seen at least one Fostex T-50 (vintage) variant made of Kapton. 

 

 

Quote:
Originally Posted by Garuspik View Post
 

I've already received custom magnets. Frankly speaking, this project started rather long ago but it's not interesting to post everything in one day ;)

 

So, before I've ordered custom magnets I've visited my local hi-end headphones store. I took with me my favourite music, screwdriver :biggrin: and whiskey (to an owner as a 'thank you' for possibility to open hi-end planar headphones and look what's inside.

 

I've listened and opened to look inside Audeze LCD 4, Hifiman He-1000, Hifiman He-560, and some less pricy Fostex. I noticed that all mentioned headphones has relatively small membrane compared to the size of the cup. I consider this to be a huge mistake in their construction.

 

Yes, the more pricy vintage Fostex T-50, it's OEM variants, as well as the Sansui SS-100 and similar Akai model, have a bigger driver. 

post #14 of 44

Very interested in progress and results.  Good job man!

post #15 of 44
Thread Starter 

Thanks! Let's continue my story. I've made several 40 ohm membranes with 0.25 traces. You can see a result on embroidery frame before glueing.

 

 

I've made on cnc router sample enclosure for measurements and listening tests.

 

 

 

What's the main difference between my designh and hifiman or audeze? Big membrane (82 mm diameter) that is capable to move lot's of air while not travelling far from middle position.

Look at photos of brand headphones and you understand what I'm talking about:

1. He-1000. About 4*6 cm active area. It's only 24 sq. cm. Nothing in comparison with huge cup

 

 

2. Audeze - same story.

 

When I've assembled planar transudecer I've measured it in open space (like tweeter with low pass filter)

 

Much better result as you see. Next step is comparison with top brands in local hi-fi store! ;)

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